Abstract
The egg-drop syndrome ‘76 (EDS ‘76) caused by duck atadenovirus A (DAdV-1) infection in laying hens leads to the decrease in egg production, causing heavy economic losses in the poultry industry; thus, vaccines with high safety and immunogenicity are needed. In this study, the DAdV-1 fiber protein expressed in Escherichia coli with codon optimization showed the hemagglutination (HA) titer of 13 log2 after purification (0.6 mg/mL). Compared with inactivated EDS ‘76 vaccine, the specific pathogen-free chickens immunized with 0.4 mL fiber protein (HA titer of 11 log2) induced an equal level of HA inhibition (HI) titer and neutralizing antibodies. Meanwhile, after immunization with fiber protein, the lowest HI titer that could provide the effect to reduce egg production rate in laying hens after the challenge was 7 log2. Moreover, fiber protein with an HA titer of 7 log2 could induce an HI titer no <7 log2 in laying hens, which was equal to or higher than the lowest HI titer (7 log2) that could reduce egg production against DAdV-1 infection significantly, indicating that it is economically feasible for vaccine development. Importantly, the HI antibodies maintained at a high level up to 180 days postimmunization contribute to the clinical application of the vaccine candidate. Overall, the fiber protein produced in E. coli is an effective subunit vaccine candidate in EDS ‘76 control for its high immunogenicity and protection in chickens.
Highlights
Duck atadenovirus A, known as duck adenovirus A (DAdV-1), is responsible for the egg-drop syndrome ‘76 (EDS ‘76) in laying hens
At 14 dpi, the immunization of fiber protein induced an equal level of HA inhibition (HI) titer (9.7 ± 1.6 log2) in chickens compared with the inactivated vaccine (9.5 ± 1.5 log2), whereas at 21 and 28 dpi, the levels of HI titer induced by fiber protein were higher (11.1 ± 1.0 log2 and 12.5 ± 1.4 log2) than that of inactivated vaccine (10.1 ± 1.6 log2 and 11.5 ± 1.5 log2)
The results indicated that the fiber protein immunization reduces the impact of the drop in egg production caused by virus infection in laying hens significantly
Summary
Duck atadenovirus A, known as duck adenovirus A (DAdV-1), is responsible for the egg-drop syndrome ‘76 (EDS ‘76) in laying hens. DAdV-1 is a member of the genus Atadenovirus within the family Adenoviridae, with an ∼30- to 35-kb linear double-stranded DNA genome [1]. DAdV-1 mainly infects waterfowl like its natural host duck and geese [3]. EDS ‘76 causes a significant drop of egg production and the low quality of the eggs [4, 5]. The capsid protein of DAdV-1 contains important adenovirus-neutralizing epitopes [7]. For higher safety and immunogenicity in the vaccination, the DAdV-1 capsid protein was being used in the development of the subunit vaccine [7, 8]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
